How severe is CVE-2022-41940?

CVE-2022-41940 has a CVSS score of 7.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2022-41940?

CVE-2022-41940 affects the following packages: engine.io (npm), engine.io (npm). Ecosystems affected: npm.

How do I fix CVE-2022-41940?

Update engine.io to 3.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-41940 is resolved across your whole dependency graph.

How do I detect CVE-2022-41940 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for engine.io, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2022-41940 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2022-41940 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2022-41940, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2022-41940?

CVE-2022-41940 has an EPSS (Exploit Prediction Scoring System) score of 2.1%, placing it in the 82th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2022-41940?

CVE-2022-41940 is classified as CWE-248 (CWE-248). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2022-41940 published, and has it been updated?

CVE-2022-41940 was published on November 22, 2022 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2022-41940 — engine.io

HIGHFix: socketio/engine.io@425e833

CVE-2022-41940 is a high-severity (CVSS 7.1) CWE-248 vulnerability in engine.io. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for engine.io — see the affected versions and patch details below.

Uncaught exception in engine.io

Also known asGHSA-r7qp-cfhv-p84w

Published

Nov 22, 2022

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs82th percentile — riskier than 82% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

260other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

engine.ionpm

25.5Mdownloads / week

Description

Impact

A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process.

events.js:292
      throw er; // Unhandled 'error' event
      ^

Error: read ECONNRESET
    at TCP.onStreamRead (internal/stream_base_commons.js:209:20)
Emitted 'error' event on Socket instance at:
    at emitErrorNT (internal/streams/destroy.js:106:8)
    at emitErrorCloseNT (internal/streams/destroy.js:74:3)
    at processTicksAndRejections (internal/process/task_queues.js:80:21) {
  errno: -104,
  code: 'ECONNRESET',
  syscall: 'read'
}

This impacts all the users of the engine.io package, including those who uses depending packages like socket.io.

Patches

A fix has been released today (2022/11/20):

Version range	Fixed version
`[email protected]`	`3.6.1`
`[email protected]`	`6.2.1`

For socket.io users:

Version range	`engine.io` version	Needs minor update?
`[email protected]`	`~6.2.0`	`npm audit fix` should be sufficient
`[email protected]`	`~6.1.0`	Please upgrade to `[email protected]`
`[email protected]`	`~6.0.0`	Please upgrade to `[email protected]`
`[email protected]`	`~5.2.0`	Please upgrade to `[email protected]`
`[email protected]`	`~5.1.1`	Please upgrade to `[email protected]`
`[email protected]`	`~5.0.0`	Please upgrade to `[email protected]`
`[email protected]`	`~4.1.0`	Please upgrade to `[email protected]` (see here)
`[email protected]`	`~4.0.0`	Please upgrade to `[email protected]` (see here)
`[email protected]`	`~3.6.0`	`npm audit fix` should be sufficient
`[email protected]` and below	`~3.5.0`	Please upgrade to `[email protected]`

Workarounds

There is no known workaround except upgrading to a safe version.

For more information

If you have any questions or comments about this advisory:

Open an issue in engine.io

Thanks to Jonathan Neve for the responsible disclosure.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`engine.io`	all versions	3.6.1`npm install engine.io@3.6.1`
📦npm	`engine.io`	≥ 4.0.0&&< 6.2.1	6.2.1`npm install engine.io@6.2.1`

Affected Products

1 product · 2 configurations

Application

engine.iosocket

≥ 4.0.0 && < 6.2.1

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Engine.IO is the implementation of transport-based cross-browser/cross-d…

github.comNVDNov 2022

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for engine.io, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update engine.io to 3.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-41940 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
Red Hat Fuse 7.12	`engine.io`	RHSA-2023:3954

Frequently Asked Questions

### Impact A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. ``` events.js:292 throw er; // Unhandled 'error' event ^ Error: read ECONNRESET at TCP.onStreamRead (internal/stream_base_commons.js:209:20) Emitted 'error' event on Socket instance at: at emitErrorNT (internal/streams/destroy.js:106:8) at emitErrorCloseNT (internal/streams/destroy.js:74:3) at processTicksAndRejections (internal/process/task_queues.js:80:21) { errno: -104, code: 'ECONNRESET', syscall: 'read' } ``` This im